A service person deals with an error of an image forming apparatus according to a user manual or a service manual. Correspondingly, a cause of an error occurring in the market may be investigated and registered in a database. A system capable of quickly deciding a countermeasure when the same error occurs again is proposed.
However, the number of cause candidates of the same error is not limited to one. In other words, there may be plural cause candidates of the same error. In such a case, it is difficult to give priority to error handling procedures.